Year Percent 1950 28.79822 1955 28.45405 1960 27.99745 1965 27.5949 1970 27.1412 1975 26.9909 1980 27.47508 1985 26.67309 1990 24.12145 1995 26.94889 2000 27.00775 2005 27.1825 2010 27.18371 2015 27.40414 2020 28.075 2025 28.97082 2030 29.89855 2035 30.55779 2040 30.87938 2045 31.04728 2050 31.18697 2055 31.29593 2060 31.343 2065 31.21528 2070 30.91013 2075 30.49286 2080 30.03188 2085 29.54991 2090 29.06656 2095 28.56675 2100 28.06494